Switch routing table utilizing software defined network (SDN) controller programmed route segregation and prioritization

ABSTRACT

In one embodiment, an apparatus includes a memory, a hardware processor, and logic integrated with and/or executable by the processor. The logic is configured to receive one or more software defined network (SDN) routes dictating a path through a network comprising a plurality of devices. The logic is also configured to store the one or more SDN routes to the memory along with one or more traditional routes learned by the apparatus and/or configured by an administrator, and indicate the one or more SDN routes as being of a type different from the traditional routes. Moreover, the logic is configured to receive a priority ordering for a plurality of routes stored in the memory from the SDN controller, the plurality of routes including at least one SDN route, and construct a route information base (RIB) based on the plurality of routes and the priority ordering.

BACKGROUND

The present invention relates to network switches and switching, andmore particularly, this invention relates to using a software definednetwork (SDN) controller to segregate and prioritize SDN-controlledroutes in a switch routing table.

One goal of a SDN is to allow the network to be programmable via a SDNcontroller. The SDN controller is typically physically separated fromany of the controlled network switches, but is not necessarily locatedremotely therefrom. One method that allows for programmability of thenetwork may involve the use of the OpenFlow communication protocol.However, other applications that may allow for programmability of thenetwork either now or in the future may be used, in addition to or inplace of OpenFlow, as would be understood by one of skill in the artupon reading the present descriptions.

Other methods that allow for the network to be programmable involve moretraditional approaches, such as simple network management protocol(SNMP), network configuration protocol (NetConf), etc. In futureversions of OpenFlow, support may be added for programming layer 3 IPv4and layer 3 IPv6 Forwarding Elements via OpenFlow. Layer 3 forwardingelement programming via OpenFlow may add support to program the layer 3forwarding table, also referred to as a Forwarding Information Base(FIB). In contrast to the Routing Information Base (RIB), the FIB isoptimized for fast longest prefix match lookup of a destination internetprotocol (IP) address and may be used for data path forwarding. OpenFlowlayer 3 forwarding element programming may be used by SDN userapplications to program the layer 3 forwarding tables, in someconventional uses.

However, programming the FIB does not provide the flexibility to learnroutes via traditional methods and devices utilizing routing protocols,such as routing information protocol (RIP), open shortest path first(OSPF), border gateway protocol (BGP), etc., as well as via SDNutilizing a suitable application, such as OpenFlow or some othersuitable application known in the art. Furthermore, programming the FIBdoes not provide any method to prioritize between traditional andcalculated routes should there be any conflict.

These drawbacks to conventional techniques have consequences, such aslayer 3 SDN programming only being capable of completely replacingcurrent distributed routing protocols/algorithms. Accordingly, in orderto overcome the drawbacks of conventional systems, it would bebeneficial to have a SDN using a suitable application that is capable ofcomplementing traditional routing protocols/algorithms.

SUMMARY

In one embodiment, an apparatus includes an interface configured toconnect to one or more devices in a network, a memory, and a hardwareprocessor and logic integrated with and/or executable by the processor.The logic is configured to receive one or more software defined network(SDN) routes from a SDN controller. The logic is also configured tostore the one or more SDN routes to the memory and indicate the one ormore SDN routes as being of a type different from traditional routeslearned by the apparatus and/or configured by an administrator.

In another embodiment, a method includes receiving, using a networkswitching device, one or more SDN routes from a SDN controller. Themethod also includes storing, using the network switching device, theone or more SDN routes to a memory of the network switching device.Moreover, the method includes indicating the one or more SDN routes asbeing of a type different from traditional routes learned by the networkswitching device and/or configured by an administrator.

According to another embodiment, a computer program product includes acomputer readable storage medium having program code embodied therewith.The embodied program code is readable/executable by a device to receive,by the device, one or more SDN routes from a SDN controller. The programcode is also readable/executable to store, by the device, the one ormore SDN routes to a memory of the network switching device. Moreover,the program code is readable/executable to indicate, by the device, theone or more SDN routes as being of a type different from traditionalroutes learned by the device and/or configured by an administrator.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a network architecture, in accordance with oneembodiment.

FIG. 2 shows a representative hardware environment that may beassociated with the servers and/or clients of FIG. 1, in accordance withone embodiment.

FIG. 3 is a simplified diagram of a network system, according to oneembodiment.

FIG. 4 shows a simplified network system diagram, according to oneembodiment.

FIG. 5 shows a flowchart of a method, according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferents unless otherwise specified.

In order to overcome the drawbacks of conventional systems, it would bebeneficial to have a software defined network (SDN) using a suitableapplication, such as an application that adheres to the OpenFlowcommunication protocol or some other suitable application known in theart, that is capable of complementing traditional routingprotocols/algorithms, since this appears to be a most likely transitioncase for current implementation within an established network. Thisnetwork would allow for SDN layer 3 routes to override routes learnedvia any traditional routing protocols, possibly sometime in the future.

In one embodiment, the layer 3 entries, e.g., internet protocol (IP)address prefix and subnet mask/prefix length, may be programmed via anSDN controller to the layer 3 routing table, e.g., the RoutingInformation Base (RIB), and not to the forwarding table, e.g., theForwarding Information Base (FIB). The SDN routes may be classified intoseparate types in the RIB so that there is the ability to prioritizethese SDN routes before/over other routes learned via tradition routingprotocols, such as routing information protocol (RIP), open shortestpath first (OSPF), border gateway protocol (BGP), etc.

In one general embodiment, a system includes a network having aplurality of switches and one or more devices connected to one or moreof the plurality of switches, a software defined network (SDN)controller connected to one or more of the plurality of switches in thenetwork, the SDN controller having logic integrated with and/orexecutable by a processor, the logic being adapted to determine SDNroutes through the network between the one or more devices and each ofthe plurality of switches and send one or more SDN routes to each switchin the network capable of communicating with the SDN controller.

In another general embodiment, a SDN controller has logic integratedwith and/or executable by a processor, the logic being adapted toexecute an application to determine SDN routes through a network, eachroute including at least one switch, and send the SDN routes to at leastone switch in the network capable of communicating with the SDNcontroller, the switch being designated in the SDN routes.

According to another general embodiment, a method includes determiningSDN routes through a network between one or more devices and each of aplurality of switches and sending one or more SDN routes to each switchin the network.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as “logic,” a “circuit,” “module,” or“system,” Furthermore, aspects of the present invention may take theform of a computer program product embodied in one or more computerreadable medium(s) having computer readable program code embodiedthereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a non-transitory computer readable storage medium. Anon-transitory computer readable storage medium may be, for example, butnot limited to, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, apparatus, or device, or any suitablecombination of the foregoing. More specific examples (a non-exhaustivelist) of the non-transitory computer readable storage medium include thefollowing: a portable computer diskette, a hard disk, a random accessmemory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), a portable compact discread-only memory (CD-ROM), a Blu-ray disc read-only memory (BD-ROM), anoptical storage device, a magnetic storage device, or any suitablecombination of the foregoing. In the context of this document, anon-transitory computer readable storage medium may be any tangiblemedium that is capable of containing, or storing a program orapplication for use by or in connection with an instruction executionsystem, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a non-transitory computer readable storage medium and that cancommunicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device,such as an electrical connection having one or more wires, an opticalfiber, etc.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, radio frequency (RF), microwaves, etc.,or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++, or the like, and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on a user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer or server may be connected to the user's computerthrough any type of network, including a local area network (LAN),storage area network (SAN), and/or a wide area network (WAN), or theconnection may be made to an external computer, for example through theInternet using an Internet Service Provider (ISP). Any of the networksmay be actual physical networks or virtual networks provided by one ormore devices.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatuses(systems), and computer program products according to variousembodiments of the invention. It will be understood that each block ofthe flowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, may beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions may also be stored in a computerreadable medium that may direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

FIG. 1 illustrates a network architecture 100, in accordance with oneembodiment. As shown in FIG. 1, a plurality of remote networks 102 areprovided including a first remote network 104 and a second remotenetwork 106. A gateway 101 may be coupled between the remote networks102 and a proximate network 108. In the context of the present networkarchitecture 100, the networks 104, 106 may each take any formincluding, but not limited to a LAN, a WAN such as the Internet, publicswitched telephone network (PSTN), internal telephone network, etc.

In use, the gateway 101 serves as an entrance point from the remotenetworks 102 to the proximate network 108. As such, the gateway 101 mayfunction as a router, which is capable of directing a given packet ofdata that arrives at the gateway 101, and a switch, which furnishes theactual path in and out of the gateway 101 for a given packet.

Further included is at least one data server 114 coupled to theproximate network 108, and which is accessible from the remote networks102 via the gateway 101. It should be noted that the data server(s) 114may include any type of computing device/groupware. Coupled to each dataserver 114 is a plurality of user devices 116. Such user devices 116 mayinclude a desktop computer, laptop computer, handheld computer, printer,and/or any other type of logic-containing device. It should be notedthat a user device 111 may also be directly coupled to any of thenetworks, in some embodiments.

A peripheral 120 or series of peripherals 120, e.g., facsimile machines,printers, scanners, hard disk drives, networked and/or local storageunits or systems, etc., may be coupled to one or more of the networks104, 106, 108. It should be noted that databases and/or additionalcomponents may be utilized with, or integrated into, any type of networkelement coupled to the networks 104, 106, 108. In the context of thepresent description, a network element may refer to any component of anetwork.

According to some approaches, methods and systems described herein maybe implemented with and/or on virtual systems and/or systems whichemulate one or more other systems, such as a UNIX system which emulatesan IBM z/OS environment, a UNIX system which virtually hosts a MICROSOFTWINDOWS environment, a MICROSOFT WINDOWS system which emulates an IBMz/OS environment, etc. This virtualization and/or emulation may beenhanced through the use of VMWARE software, in some embodiments.

In more approaches, one or more networks 104, 106, 108, may represent acluster of systems commonly referred to as a “cloud.” In cloudcomputing, shared resources, such as processing power, peripherals,software, data, servers, etc., are provided to any system in the cloudin an on-demand relationship, thereby allowing access and distributionof services across many computing systems. Cloud computing typicallyinvolves an Internet connection between the systems operating in thecloud, but other techniques of connecting the systems may also be used,as known in the art.

FIG. 2 shows a representative hardware environment associated with auser device 116 and/or server 114 of FIG. 1, in accordance with oneembodiment. FIG. 2 illustrates a typical hardware configuration of aworkstation having a central processing unit 210, such as amicroprocessor, and a number of other units interconnected via a systembus 212, according to one embodiment.

The workstation shown in FIG. 2 includes a Random Access Memory (RAM)214, Read Only Memory (ROM) 216, an I/O adapter 218 for connectingperipheral devices such as disk storage units 220 to the bus 212, a userinterface adapter 222 for connecting a keyboard 224, a mouse 226, aspeaker 228, a microphone 232, and/or other user interface devices suchas a touch screen, a digital camera (shown), etc., to the bus 212,communication adapter 234 for connecting the workstation to acommunication network 235 (e.g., a data processing network) and adisplay adapter 236 for connecting the bus 212 to a display device 238.

The workstation may have resident thereon an operating system such asthe MICROSOFT WINDOWS Operating System (OS), a MAC OS, a UNIX OS, etc.It will be appreciated that a preferred embodiment may also beimplemented on platforms and operating systems other than thosementioned. A preferred embodiment may be written using JAVA, XML, C,and/or, C++ language, or other programming languages, along with anobject oriented programming methodology. Object oriented programming(OOP), which has become increasingly used to develop complexapplications, may be used.

The FIB is a layer 3 construct for fast forwarding of layer 3 packets.Some layer 2 information, such as a next hop's MAC address, VLAN,outgoing interface (port), etc., may be embedded in the FIB in order toaid in determining where to send packets on layer 2 network connections.In contrast, the RIB is a layer 3 only construct. Layer 3 IP addressprefix and prefix length are programmed by the SDN controller viaOpenFlow or some standard or proprietary interface, like SNMP, NetConf,CLI scripts, interface to routing system (I2RS), etc., to the controlledswitches. This layer 3 information is proposed to be programmed to thelayer 3 routing table and/or the RIB, rather than the FIB. The I2RS isan Internet Engineering Task Force (IETF) draft that is currently beingcreated. I2RS also proposes to be programming the RIB rather than theFIB, similar to some embodiments described herein.

The SDN routes may be classified according to a separate type in the RIBso that there is a way to distinguish these routes from all the otherroutes in the RIB. One way that this distinction may be used is toprioritize these SDN routes, possibly by making these SDN routes have ahigher priority than the other routes statically programmed (such as bya user, administrator, application, etc.) or learned via traditionalrouting protocols (such as RIP, OSPF, BGP, etc.). Since the SDN routemay be classified into a separate route type—a network administrator maydecide to prioritize the SDN routes over any other type of route for allof the controlled switches, a portion of the controlled switches,controlled switches individually, etc. In one embodiment, the networkadministrator may accomplish this prioritization by setting anadministrative distance of SDN routes to be a higher priority than theOSPF, BGP, RIP and/or static routes.

In one approach, the RTM may determine which routes are preferred basedon administrative distance of the protocol and/or by policies set by theconfigured route maps. SDN works in conjunction with the existingrouting protocols and makes it a contributor, and perhaps SDN routes aregiven some preference.

The network administrator or some other user or application may also addpolicies governing certain SDN routes to be prioritized over the otherroute types. This may be accomplished by configuring appropriateroute-maps for particular SDN routes, according to one approach, eitherautomatically or manually.

In essence, any SDN route may be treated similarly to any other routetype in the RIB, except that it may be of a SDN type. Therefore, thefollowing route types may be included in the RIB—connected interface,static routes, external BGP, OSPF, RIP, intermediate system tointermediate system (IS-IS), internal BGP, and SDN routes. Of course,other route types not specifically enumerated here may also be included,and may have their own routing type designation or simply be consideredone of the other routing types.

According to one embodiment, a traditional network may function mostlyas it currently does (e.g., with distributed route algorithms), withsome override input from SDN applications running on a central SDNcontroller, such that any SDN application may specify a separatetreatment for certain routs. Thus, there will be reduced barriersstanding in the way of SDN adoption for current networks and migrationpains may be significantly reduced as compared to a complete overhaul ofdistributed routing algorithms by central topology discovery routingalgorithms, as would be necessary without the methods and systemsdescribed herein.

Now referring to FIG. 3, a simplified diagram of a network system 300 isshown according to one embodiment. The system includes two switches 302,304, with each switch having a route table manager (RTM) 306 that iscapable of combining routes 310 from all sources 308 (e.g., connectedinterface, static routes, external BGP, OSPF, IS-IS, internal BGP, SDNroutes, etc.) to form the RIB 312. The SDN controller 314 may provideinput to the RTM 306 for each switch 302, 304 to produce SDN routes 318which may be prioritized versus other protocol routes 310 in the RIB312. Furthermore, an application 316 running on the SDN controller 314may provide the logic and/or algorithm for calculating the SDN routes318, in one approach. The application 316 may operate according toOpenFlow or some other suitable application known in the art.

Now referring to FIG. 4, a simplified diagram of a network system 400 isshown, according to one embodiment. The system 400 comprises switchesA-G 404, each switch 404 connected in a network 410 via connections 408of any known type, such as Ethernet (Cat 5, Cat5e, etc.), fiber channel(FC), optical fiber, coaxial cabling, multi-mode fiber, etc.

The switches 404 may make use of a media access control (MAC) table 412and a route table 414 within each switch 404 for choosing transmissionroutes between devices in the network 410, depending on whether thetraffic is layer 2 or layer 3. The MAC table 412 may be used todetermine destination addresses for layer 2 traffic, while the routetable 414 may be used to determination routes for delivery of layer 3traffic.

With a SDN 410, route calculation functionality for each of the switches404 may be moved from the processors (CPUs) of the switches 404 to adifferent system which is not a switch or a router, but more of ageneral purpose computer which may be referred to as the SDN controller402. The SDN controller 402 may perform the route calculations and sendthe route calculations to the switches 404, but not necessarily theroute information. Thus, one approach essentially moves away from adistributed mechanism, to a centralized mechanism, where a controller402 is learning everything about the whole network 410 and configuresthe route tables 414 and MAC tables 412 in a status which ultimately isused to decide which packet is delivered through which route.

This approach is not expected to be readily accepted, because it isdifferent than what has been in use for the last 20 years or so.However, with a SDN 410, the system 400 may receive input fromapplications to decide specifically which routes to use. This ispreferred, and is a hybrid kind of network, which may also leveragedistributor routing protocols analysis. User controls may also beprovided to provide a measure of control over these routes, as well assetting priorities between these routes. In a preferred embodiment,instead of putting information in the MAC table (also referred to as aforwarding table) 412, it is put in the route table 414 and used as adifferent route type. If the SDN programmed route is not present as adifferent route type, the route may only be programmed as a static routeor an existing route type, and the system will not be able todistinguish between OpenFlow/SDN routes and existing route types (forexample static route). One embodiment provides control over the behaviorwhen choosing between SDN routes and existing route types.

In a sense, the SDN controller 402 may create or have a route similar tothat which is learned by the traditional protocols OSPF, BGP, staticroutes, etc. Some routes may be learned based on protocols, such asOSPF, BGP, etc. These routes may be considered along with the SDNroutes, in one approach. In another approach, SDN routes may beconsidered in addition to static routes.

The system 400 includes the SDN controller 402 adapted for determiningSDN routes through the network 410, possibly based on one or moreapplications operating on the SDN controller 402, such as OpenFlow. TheSDN routes may be included in a RIB on each switch A-G 404, along withother route types determined according to other methods, such as staticroutes, BGP, OSPF, etc.

The SDN controller 402 may be connected to one or more switches 404 viaone or more connections 406 of a type known in the art, such as out-ofband management paths, control channel (in an out-of-path Ethernetconnection), Ethernet, FC, optical fiber, coaxial cabling, multi-modefiber, etc.

For the sake of simplicity, the route table 414 and MAC table 412 areshown as single entities; however, as stated previously, each switch 404includes each of the tables therein, and the SDN controller 402 iscapable of accessing and modifying each table in each switch 404separately.

In one embodiment, the SDN routes may be considered as higher inpriority versus routes created using other protocols and/or staticroutes, depending on any number of factors, such as administrativedistance. An administrative distance may be configured on a switch 404that instructs the switch 404 to prefer all of one type of route overanother. For example, OSPF routes may be preferred compared to all BGProutes. In one approach, the switch 404 may able to choose which type ofroute to use between all types of routes available in the route table414.

In further embodiments, which routes to use may be determined solely bythe SDN controller 402 upon full integration with the system 400 therebyrendering the other protocols as unnecessary. However, even when thisfull integration occurs, the other protocols may continue to operate, incase any legacy or previously installed systems or devices continue tomake use of the routes provided by the other protocols.

The routing determinations for the network 410 are usually performed bythe distributor of the routing protocols. In one approach, thedistributor of the routing protocols may be the SDN controller 402.There are algorithms that exchange information between each switch 404in the network 410, and these algorithms may ultimately come up withwhat is called a route table based on the exchange of that information.Conventionally, there is a route table 414 in each switch 404. Each ofthese route tables may be programmed from different design protocols, orthey may be statically configured. A routing protocol may also provideroutes to the route table 414, and these route tables 414 may learn fromdifferent sources, using different routing protocols. In one approach, auser may configure the route table 414 in each switch 404.

In a typical networking system, the way that protocol modules interactis by choosing the best routes through the network 410. There may be anyorder of protocol preference which is used to determine what isconsidered a best route over some other route. In addition, an internalpriority mechanism may be used to determine which protocol's routes arepreferred. For example, OSPF routing protocol is typically givenpriority over RIP routing protocol. Therefore, all of those heuristicswill be used to determine a route table 414 which all of these selectedroutes are stored in.

In one embodiment, in addition to these other protocols, the SDNcontroller 402 will provide an additional input to the route table 414.In another embodiment, the SDN controller 402 may allow the traditionalrouting protocols to run as normal, the SDN controller 402 may read theroute table 414, modify the routes in some way based on knowledge of thenetwork 410, and then reprogram the routes in the route table 414. Inthis way, a feedback loop is provided in the designation of the routesin the route table 414.

Several decisions may be performed by the SDN controller 402, because itmight have inputs associated with how the applications are running inthe network 410.

Various applications may talk with the SDN controller 402, and may evendrive the route algorithms in some particular cases. In one approach,one or more applications may operate on the SDN controller 402.

In various embodiments, the way that SDN controllers 402 are implementedis that they alter flow tables. For example, in each switch 404, a routetable 414 is in the hardware. The hardware entities may have a layer 2table which deals with the MAC addresses only (MAC table 412) andperhaps a layer 3 table (route table 414). Also present is a flow table416, sometimes referred to as access control lists (ACLs) or some othername, the filter processor, or filter table, which has conversationswith devices in the network 410. These conversations may be as genericor specific as desired. The best match is found for a route through thenetwork 410 and the route table 414 is populated with these routes.

RIB refers to a route table 414, FIB refers to a forwarding table or MACtable 412, which is not necessarily the same as the flow table 416.

In one approach, the difference between the route table 414 and the flowtable 416 is as follows: the flow table 416 defines a route from oneplace in the network 410 to another place in the network 410, or fromeverywhere in the network 410 to somewhere in the network 410. Itcaptures a certain flow and some sort of communication that is headedsomewhere or came from some destination. The route table 414 is going tospecifically designate a route on a preferential basis.

In one embodiment, the route table 414 may specify a route to a givenswitch 404 or to a specific destination, or it is going to an endlocation somewhere and a route specifying how it is going to get there.Conceptually, it is a template for all of those devices. It may specifythe classes of the addresses. It may specify how to get to an IPaddress.

In another embodiment, the system 400 performs a centralized computationand programs the flow table 416, optionally in conjunction with, andpreferentially over, the network operating in a distributed manner withthe switches 404 running protocols in a distributed manner and tables412, 414 being computed on each switch 404.

One approach may be a hybrid system where everything else is running ina known manner, but the SDN controller 402 generates a preferred route,and in the route table 414, such route is segregated as a different SDNroute type. This particular approach of having it as a different type iswhat allows rules to be applied to specific types of routes as a routemap.

Prioritization of routes may be based on rules programmed into eachswitch 404 or administrative preferences, in various approaches.Preferences may be set by the administrator or may be based on the routemaps. So the administrator may be given control on how the preferencesare set up.

In one approach, the software-defined route is sent to each switch 404and then, based on either the administrative preferences or somethingelse, the switch 404 will pick which route to use. In another approach,the SDN controller 402 may specify that the software-defined route is tobe given priority.

Now referring to FIG. 5, a method 500 is shown according to oneembodiment. The method 500 may be performed in accordance with thepresent invention in any of the environments depicted in FIGS. 1-4,among others, in various embodiments. Of course, more or less operationsthan those specifically described in FIG. 5 may be included in method500, as would be understood by one of skill in the art upon reading thepresent descriptions.

Each of the steps of the method 500 may be performed by any suitablecomponent of the operating environment. For example, in one embodiment,the method 500 may be partially or entirely performed by a SDNcontroller, a processor (such as a CPU, an ASIC, an FPGA, etc.), amodule, a function block, a switch, a router, etc., in variousapproaches.

As shown in FIG. 5, method 500 may initiate with operation 502, whereSDN routes through a network between one or more devices and each of aplurality of switches are determined. The SDN routes are determined bythe SDN controller or some other suitable device or processor in thenetwork, or capable of analyzing the network and network connections.

In operation 504, one or more SDN routes are sent to each switch in thenetwork. In one approach, only those switches which are capable ofcommunicating with the SDN controller may be sent the SDN routes. Inanother embodiment, all switches are sent the SDN routes, and only thoseswitches which understand the information store them. According toanother embodiment, all switches in the network are capable ofcommunicating with the SDN controller.

In operation 506, the one or more SDN routes are received using at leastone switch in the network. The one or more SDN routes sent to the switchare specific to that switch, e.g., the SDN routes are tailored for thatspecific switch, and only routes which concern that particular switchare sent to it. Different SDN routes are sent to each different switchdepending on the connections that each switch has.

In operation 508, the one or more SDN routes are stored to a locationaccessible by the at least one switch. For example, they may be storedto a route table, flow table, or some other medium that the switch mayview, manipulate, or otherwise have access to. This storage operationmay be performed by the switch.

In operation 510, the one or more SDN routes are indicated as being atype different from traditional routes learned by the at least oneswitch and/or configured by an administrator. This may be accomplishedusing a flag, a marker, a bit, or any other method of indicating astate, status, type, or difference. The other routes accessible to theswitch may all have the same or different marker, or they may beindicated as belonging to their own individual groups. For example, eachroute from OPSF may be indicated as such, each SDN route may beindicated as such, each IS-IS route may be indicated as such, etc. Inthis way, the switch will be aware of which type of route it can choosefrom.

In operation 512, a priority ordering is determined for a plurality ofroutes stored in the location accessible by the at least one switch. Theplurality of routes includes at least one SDN route, and may includemany other different types of routes. In addition, more than one SDNroute may also be included, and priority ordering may be performed onthem all.

By ordering the routes according to priority, it may be determined whichroutes will be best for specific different scenarios. For example, lowlatency tasks, high speed tasks, important tasks, etc., may all be bestserved by choosing a different route through the network between aningress and an egress port. The priority ordering may take all of thisinto account when determining the ordering.

In one embodiment, SDN routes may be allocated a higher priority thannon-SDN routes.

In operation 514, a RIB is constructed based on the plurality of routesand the priority ordering. This may be performed by the switch or by theSDN controller for each switch. The RIB is stored local to the switch sothat the switch has access to the RIB.

In operation 516, a route is chosen from the RIB to send traffic throughthe network based at least partially on the priority ordering. Thenature of the traffic may also be taken into consideration when choosinga route, along with network congestion, network failures, devicefailures, alerts and warnings, specific requests that accompany thetraffic (such as a request for low latency switches, etc.), or any otherfactor capable of affecting a route through the network.

In operation 518, the traffic is sent along the chosen route, such as byforwarding the traffic to a first hop as designated by the chosen route.

In one embodiment, which route to choose may be dictated prior to makingthe choice. For example, if the switch is choosing the route, the SDNcontroller may dictate to the switch which route to choose.

In another embodiment, the SDN controller may be further adapted tomodify the RIB to alter the priority ordering of the routes prior to theswitch choosing a route from the RIB.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. An apparatus, comprising: an interface configuredto connect to one or more devices in a network; a memory; and a hardwareprocessor and logic integrated with and/or executable by the processor,the logic being configured to: receive one or more software definednetwork (SDN) routes from a SDN controller; store the one or more SDNroutes to the memory; indicate the one or more SDN routes as being of atype different from traditional routes learned by the apparatus and/orconfigured by an administrator; choose a route from the memory to sendtraffic through the network; and send the traffic along the chosenroute.
 2. The apparatus as recited in claim 1, wherein the one or moreSDN routes are specific to the apparatus as opposed to other devices inthe network.
 3. The apparatus as recited in claim 1, wherein the logicintegrated with and/or executable by the processor is configured to:determine a priority ordering for a plurality of routes stored in thememory, the plurality of routes including at least one SDN route; andconstruct a route information base (RIB) based on the plurality ofroutes and the priority ordering.
 4. The apparatus as recited in claim3, wherein SDN routes stored in the memory are allocated a higherpriority than non-SDN routes stored in the memory.
 5. The apparatus asrecited in claim 3, wherein the logic integrated with and/or executableby the processor is configured to: choose a route from the RIB to sendtraffic through the network based at least partially on the priorityordering; and send the traffic along the chosen route.
 6. The apparatusas recited in claim 1, wherein the logic integrated with and/orexecutable by the processor is configured to accept instruction from theSDN controller dictating a route to choose from the memory.
 7. Theapparatus as recited in claim 5, wherein the logic integrated withand/or executable by the processor is configured to accept modificationsof the RIB from the SDN controller, the modifications altering thepriority ordering of the routes prior to a route being chosen from theRIB.
 8. The apparatus as recited in claim 1, wherein communications withthe SDN controller occur according to OpenFlow.
 9. A method, comprising:receiving, using a network switching device, one or more softwaredefined network (SDN) routes from a SDN controller; storing, using thenetwork switching device, the one or more SDN routes to a memory of thenetwork switching device; and indicating the one or more SDN routes asbeing of a type different from traditional routes learned by the networkswitching device and/or configured by an administrator; choosing a routefrom the memory to send traffic through the network based at leastpartially on a type of the route; and sending the traffic along thechosen route.
 10. The method as recited in claim 9, wherein the one ormore SDN routes are specific to the network switching device as opposedto other devices in the network.
 11. The method as recited in claim 9,comprising: determining a priority ordering for a plurality of routesstored in the memory, the plurality of routes including at least one SDNroute; and constructing a route information base (RIB) based on theplurality of routes and the priority ordering.
 12. The method as recitedin claim 11, wherein SDN routes stored in the memory are allocated ahigher priority than non-SDN routes stored in the memory.
 13. The methodas recited in claim 11, comprising: choosing a route from the RIB tosend traffic through the network based at least partially on thepriority ordering; and sending the traffic along the chosen route. 14.The method as recited in claim 13, comprising accepting instruction fromthe SDN controller dictating which route to choose.
 15. The method asrecited in claim 13, comprising accepting modifications of the RIB fromthe SDN controller, the modifications altering the priority ordering ofthe routes prior to a route being chosen from the RIB.
 16. The method asrecited in claim 9, wherein communications with the SDN controller occuraccording to OpenFlow.
 17. A computer program product, comprising acomputer readable storage medium having program code embodied therewith,the embodied program code readable/executable by a device to: receive,by the device, one or more software defined network (SDN) routes from aSDN controller; store, by the device, the one or more SDN routes to amemory of the network switching device; indicate, by the device, the oneor more SDN routes as being of a type different from traditional routeslearned by the device and/or configured by an administrator; determine,by the device, a priority ordering for a plurality of routes stored inthe memory, the plurality of routes including at least one SDN route;choose, by the device, a route from the memory to send traffic throughthe network based at least partially on the priority ordering; and send,by the device, the traffic along the chosen route.
 18. The computerprogram product as recited in claim 17, wherein the one or more SDNroutes are specific to the network switching device as opposed to otherdevices in the network.
 19. The computer program product as recited inclaim 17, wherein the embodied program code is furtherreadable/executable by the device to: construct, by the device, a routeinformation base (RIB) based on the plurality of routes and the priorityordering.
 20. The computer program product as recited in claim 19,wherein SDN routes stored in the memory are allocated a higher prioritythan non-SDN routes stored in the memory.